The present invention relates to a method for inspecting a connected portion of a filler in which a strip of a filler is adhered to the outer circumference of a bead core for a vehicle tire, the two end surfaces of the filler are adhered and connected to each other, and then the state of the connected portion is inspected.
As shown in FIG. 11, in a typical vehicle tire, an annular bead core 52 and an annular filler 53 are embedded in the inner rim of each of the two sidewalls of a tire rubber 51. A strip of the filler 53 is adhered to the outer circumference of the bead core 52 in advance as shown in FIG. 12A. Then, the two end surfaces 531 and 532 are adhered and connected to each other as shown in FIGS. 12B and 13 so that the filler 53 attached to the bead core 52 becomes annular. Patent document 1 discloses a structure in which a filler is adhered to the outer circumference of a bead core, and the two end surfaces of the filler are connected to each other.
When the filler 53 is attached to the bead core 52 in this manner, a connection defect may occur at the portion where the two end surfaces 531 and 532 of the filler 53 are connected as shown in FIGS. 14A to 14D. More specifically, FIG. 14A shows a situation in which a gap is formed in the outer circumferential end of the connected portion. FIG. 14B shows a situation in which a step is formed in the outer circumferential end of the connected portion. FIG. 14C shows a situation in which a gap is formed in the middle of the connected portion. FIG. 14D shows a situation in which the end surfaces of the connected portion are displaced in the thickness-wise direction.